Flooding is an annual phenomenon in India's northeast, claiming hundreds of lives each year.

"The flood situation is grim in Assam. More than a million people have been hit by this year's" rising waters, Assam Disaster Management Authority's state project co-ordinator, Pankaj Chakravarty, said.

The state was first hit in mid-May when pre-monsoon rains arrived, causing floods that killed 11 people. Another 20 died in landslides caused by days of incessant downpours.

An Indian villager walks with his cattle through floodwaters at Buraburi village in Morigoan district of Assam state. — AFP/VNA Photo

The floodwaters receded after a few weeks, only to rise again on June 22 at the start of the annual monsoon season.

Almost 29,000 people, mostly in rural regions, have been evacuated from their homes and brought to relief camps, officials said.

About 70 per cent of Assam's World Heritage-listed Kaziranga National Park – home to two-thirds of the world's remaining one-horned rhinos – was submerged by the floods.

Park director P. Sivakumar said three hog deer died when they were hit by vehicles while trying to escape the inundation.

"With the water level rising, the animals are rushing to higher areas. Many of these animals cross the highway," Sivakumar said.

The monsoon is crucial to replenishing water supplies in South Asia, but also causes widespread death and destruction across the region each year. — AFP